SURFACE-MODIFIED CALCIUM HYDROGENPHOSPHATE AND SURFACE COATING METHOD

摘要

PURPOSE:To obtain surface-modified calcium hydrogenphosphate having characteristics as an abrasive for dentifrice such as good flavor and crispness and also having improved stability to fluorine by coating the surface of calcium hydrogenphosphate with hydroxyapatite. CONSTITUTION:Calcium hydrogenphosphate is brought into contact with an alkali metal or alkaline earth metal hydroxide or NH3 in an aq. suspension to coat the surface of the calcium hydrogenphosphate with 1-90wt.% hydroxyapatite. The concn. of the calcium hydrogenphosphate in the aq. suspension is <=80wt.%, preferably 50wt.%. The alkali is used as 2-8wt.% soln. in case of NaOH or KOH or as 10-30wt.% soln. in case of NH3.